C#过滤sql注入关键字防止sql注入

 public static string Filter(string Htmlstring)
        {
            if (Htmlstring == null)
            {
                return "";
            }
            else
            {
                //删除脚本
                Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "", RegexOptions.IgnoreCase);
                //删除HTML
                Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"([\r\n])[\s]+", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", "\"", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&(lt|#60);", "<", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&(gt|#62);", ">", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", " ", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "\xa1", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "\xa2", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "\xa3", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "\xa9", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, @"&#(\d+);", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "xp_cmdshell", "", RegexOptions.IgnoreCase);

                //删除与数据库相关的词
                Htmlstring = Regex.Replace(Htmlstring, "select", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "insert", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "delete from", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "count''", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "drop table", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "truncate", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "asc", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "mid", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "char", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "xp_cmdshell", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "exec master", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "net localgroup administrators", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "and", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "net user", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "or", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "net", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "delete", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "drop", "", RegexOptions.IgnoreCase);
                Htmlstring = Regex.Replace(Htmlstring, "script", "", RegexOptions.IgnoreCase);

                //特殊的字符
                Htmlstring = Htmlstring.Replace("<", "");
                Htmlstring = Htmlstring.Replace(">", "");
                Htmlstring = Htmlstring.Replace("*", "");
                Htmlstring = Htmlstring.Replace("-", "");
                Htmlstring = Htmlstring.Replace("?", "");
                Htmlstring = Htmlstring.Replace("'", "''");
                Htmlstring = Htmlstring.Replace(",", "");
                Htmlstring = Htmlstring.Replace("/", "");
                Htmlstring = Htmlstring.Replace(";", "");
                Htmlstring = Htmlstring.Replace("*/", "");
                Htmlstring = Htmlstring.Replace("\r\n", "");
                return Htmlstring;
            }
        }